The present invention relates to a master-slave mechanical manipulator with homothetic displacements.
It is known that manipulators of the master-slave type are manipulators in which there is on the one hand a master arm provided at its end with a control handle which is operated by the operator and on the other hand a slave arm controlled by the master arm and which carries a tool at its end. By controlling the movement of the different components of the master arm the operator causes corresponding movements of the different components of the slave arm, thus making it possible to move the tool fixed to the end of the slave arm. Conversely any movement imposed on the tool is reproduced by the control handle. Thus, any load applied to the tool is restored to the operator by the control handle. It is also known that certain of these manipulators are operated by motors, i.e. there is no direct mechanical connection between the movements of the master arm and the movements of the slave arm and instead there is a servocontrol of the motors controlling the two arms and providing the load return referred to hereinbefore.
The present invention relates to non-motorized manipulators, i.e. in which there is a direct mechanical transmission between the master arm and the slave arm.
A number of non-motorized manipulators are already known which have a master arm and a slave arm articulated to the ends of a shaft mounted in pivotal manner with respect to a fixed support. Certain of these manipulators have master and slave telescopic arms of the same size and having a displacement movement leading to the said two telescopic arms forming a relative angle which can reach at least 45.degree.. Under these conditions any displacement of the control handle in the plane of the arm leads to a ssuperimposable slave tool displacement after a rotation having its centre in the plane of the arm.
When the slave arm and the master arm have different lengths the transformation making it possible to pass from master displacement to slave displacement becomes a similitude.
In addition, articulated manipulators are known having complex movements leading to a non-linear transformation of the displacements, which simultaneously causes the distortion of straight lines and angles.
In all three cases the operator is inconvenienced by the disorientation due to the similitude rotation angle and/or the linear and angular distortion. It is readily apparent that the vertical displacement of the heavy load causes considerable difficulities for the operator when the handle has to follow an oblique or curved path.